Long-Term debt obligations - Leverage Ratio on which Spread on Libor Borrowings and Commitment Fee for Unused Balance of Revolving Credit Agreement are Determined (Detail)	12 Months Ended
	Oct. 31, 2017
25%
Line of Credit Facility [Line Items]
Leverage ratio (as a percentage)	25.00%
Spread	0.25%
Commitment Fee	0.20%
≥ 25% and 35%
Line of Credit Facility [Line Items]
Spread	0.50%
Commitment Fee	0.25%
≥ 25% and 35% | Minimum
Line of Credit Facility [Line Items]
Leverage ratio (as a percentage)	25.00%
≥ 25% and 35% | Maximum
Line of Credit Facility [Line Items]
Leverage ratio (as a percentage)	35.00%
≥ 35% and 45%
Line of Credit Facility [Line Items]
Spread	1.00%
Commitment Fee	0.30%
≥ 35% and 45% | Minimum
Line of Credit Facility [Line Items]
Leverage ratio (as a percentage)	35.00%
≥ 35% and 45% | Maximum
Line of Credit Facility [Line Items]
Leverage ratio (as a percentage)	45.00%
≥ 45%
Line of Credit Facility [Line Items]
Leverage ratio (as a percentage)	45.00%
Spread	1.50%
Commitment Fee	0.35%